Environmental Control Programs the Emergence of Distinct Product Ensembles from Unconstrained Chemical Reaction Networks

Abstract

<p><b>Harnessing and then controlling </b><b>combinatorial explosions</b><b> in </b><b>uncontrolled condensation reactions of simple building blocks is a key problem to many hypotheses on the origin</b><b> of </b><b>life. Much has been achieved in understanding how the building blocks of biopolymers may be formed, and in understanding how macromolecules may produce functional and increasingly life-like systems. How</b><b> these </b><b>steps can be joined, and how defined populations</b><b> of </b><b>macromolecules can form from mixtures</b><b> of </b><b>simple building blocks, instead of an undifferentiated </b><b>mess</b><b>, remain open questions.</b><b> Herein, we show </b><b>how</b><b> unconstrained </b><b>condensation</b><b> reactions of both amino acids, and prebiotic soup mixtures produced by spark discharge, can be steered</b><b> by changes in the reaction environment, such as order of reactant addition (mixing history), and addition of salts or minerals. Using </b><b>techniques akin to untargeted metabolomics</b><b> to survey product distributions we</b><b> demonstrate that while these reactions do produce a large range of species, there are distinct, significant, and reproducible differences between the product ensembles</b><b>. Furthermore, we observe that differences in composition </b><b>are </b><b>demonstrated through</b><b> clearly different structural and functional properties. </b><b>Using this approach, we demonstrate for the first time that simple variations in environmental parameters can mediate the differentiation of distinct ensembles from both amino acid mixtures and a classic primordial soup model (products of a ‘Miller Urey’ type spark discharge reaction). </b><b>This shows that </b><b>the synthetic complexity produced by such unconstrained reactions is not as intractable as often suggested, when viewed through a chemically agnostic lens. An open</b><b> approach to complexity can generate compositional, structural, and functional diversity from fixed sets of simple starting materials, suggesting that differentiation of product mixtures can occur in the wider environment without the need for biological machinery.</b><b></b></p>

Emergence of Function and Selection from Recursively Programmed Polymerisation Reactions in Mineral Environments

“…3), demonstrating the robust effects of chemical recursion in this system. In previous work, we examined the ability of minerals and salts to influence the product distribution of similar uncontrolled condensation reactions, 17 and minerals have been studied extensively for their ability to concentrate amino acids on their surface, as well as catalyse aqueous peptide polymerisation driven by activating agents 18 and wet-dry cycles. "L" = leucine; "E" = glutamic acid; "K" = lysine.…”

Taming Combinatorial Explosion of the Formose Reaction via Recursion within Mineral Environments

“…However, the interaction of simple molecules with the environment has been proven to steer the chemical networks into different outcomes or product populations, giving them a higher level of order as a result of environmental constraints (such as inorganic catalysts). [17][18][19][20] In particular, the presence of mineral surfaces is known to sometimes truncate the combinatorial explosions generated by one-pot reaction of simple compounds. Two relevant examples are the preferential formation of ribose when borate minerals were added to the formose reaction, [21] a system known for the incredible complexity of its product distribution, and the clear selectivity towards the production of certain nucleobases when formamide condensation was carried out on different mineral surfaces.…”